Seth Rogen unsure he will star in Knocked Up spin-off

Seth Rogen was surprised to hear about the planned 'Knocked Up' spin-off movie.

The actor starred in the original movie about a slacker who finds out a woman he had a one-night stand with is pregnant and although Seth knew writer / director Judd Apatow was working on new material, he is unsure if there will be a role for him.

He said: "Judd mentioned it to me off-handedly a year ago, and then I just read about it just like everybody else. I was like, 'Oh man, it looks like it's really happening.'

"So, I don't know. I'm going to call him and see what the deal is."

The as-yet untitled film will star Paul Rudd and Leslie Mann- who played married couple Pete and Debbie in the first movie - because according to Judd audiences loved their characters.

He said: "It is just a story from Pete and Debbie's current life. People really responded to their characters and problems. I felt like there was a lot of ground I could explore with them, so we'll be shooting in July and will come out the following June. "There are some fun details yet to reveal but I will let them come out slowly. It's more fun that way."